1. Technical Field
The embodiments disclosed herein are related to the field of manufacturing light emitting diode (LED) devices.
2. Background and Relevant Art
Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. The use of the term “background” is inclusive of the term “context.” Thus, the following section provides both context for the disclosure and may also provide patentable support for the claims.
The use of doped semiconductors to create barriers, injectors, tunnel junction contacts, cascade LED junctions, and other related devices has long been known in the art. Specially, conventional semiconductor materials can be comprised of doped semiconductor layers placed into contact with each other to create one or more p-n junctions. In the case of light emitting diodes (LEDs), as electrical current is applied to the junctions, electrons and holes combine with each other and emit photons. The energy contained in the emitted photons corresponds to the energy difference between the respective holes and electrons.
Conventional LED device dies have dimensions around one millimeter square and a tenth of a millimeter thick. The die substrates have thin semiconductor heterostructure layers on one side, with the layers patterned by lithography for making electrical contact. Forcing an electrical current through the heterostructure layers can convert electrical power to optical power. Light generated within the heterostructures can be extracted from a die with combinations of surface features and coatings, such that light can escape which would otherwise be mostly confined to the die because of total internal reflection.
Several conventional semiconductor device fabrication methods have been developed for high-brightness and other format LEDs that operate at particular wavelengths in several optical wavelength ranges, including the ultraviolet, visible, and near-infrared ranges. A conventional LED fabrication method typically includes several processes and procedures. First, the fabrication process can include processes for the epitaxial growth of light emitting and other semiconductor layers on a substrate. Second, the fabrication can include a process for lithographically patterning the epitaxial and other layers to define electrical contacts. Third, the fabrication can include a process for adding optical layers and features for light extraction. Fourth, the fabrication can include a process for configuring the device die for packaging. Fifth, the fabrication can include a process for then packaging die by attaching and bonding the die for electrical contact and thermal heat sinking. One will understand that the processes described above are merely exemplary and that other embodiments may comprise additional, fewer, or different process steps.
Conventional LEDs operating in different wavelength ranges are based on different semiconductor material systems. These conventional LEDs typically require different corresponding chemical fabrication processes as well as particular supporting metal and dielectric materials combinations compatible with the respective semiconductor materials. Due to limitations in the current art, conventional fabrication methods cannot be applied to a semiconductor material system that spans the mid-infrared wavelength range.
Accordingly, there are a number of improvements that can be made within the art.